Though he did not play and was only listed as a reserve, the time spent amongst established veterans and exciting young players hoping to make the Opening Day roster was invaluable.
"The message to Moniak is that it's great to get your feet wet and just be around the Major League players, in that Major League clubhouse and in that Major League dugout," Phillies manager Gabe Kapler said. "That's a great first step. It doesn't need to be a big moment on the field -- just feel confident and comfortable in the environment. Mickey was able to accomplish that task today."
Moniak said he found out Friday that he would be with the team, and he has been working on getting acclimated to the Florida climate for the past two weeks in preparation for Minor League camp following a productive offseason.
"I've worked hard to maintain my body and make sure that it's ready for 140 games," Moniak said. "Just to get mentally ready for 140 games is a huge thing for me."
He added that Kapler has been helpful in guiding him about how to conduct himself.
"Just keep working hard, because they're going to have their eyes on me," Moniak said was Kapler's message. "Play hard, work hard and good things will happen. He's an intense guy and it's awesome."
Moniak didn't waste any time in showing what he could do in 2016, playing for the Phillies' Rookie Level team in the Gulf Coast League. In 46 games, Moniak hit .284 with 16 extra-base hits while posting a .340 on-base percentage.
However, 2017 wasn't as kind.
Playing for Class A Lakewood, Moniak's offensive output tailed off in his first full season in the pros, as he went just .236/.284/.341.
"I'm actually grateful for last season, because it's the first time in my life that I had to bear down after struggling for a while," Moniak said. "I definitely learned a lot about myself. Preparing my body for 140 games -- I did a better job of it this year. There was some good, there was some bad, but I'm excited for this year."
Despite the rough year, Moniak is still considered to be a large part of Philadelphia's future plans. He helps bolster a deep farm system which is ranked fifth by MLB Pipeline. Moniak, who is just 19, is ranked No. 88 in all of baseball. Last year, he was ranked No. 19. He's the Phils' No. 5 prospect after finishing 2017 as the club's No. 1 prospect.
He embraced the slide in the rankings.
"I'm kind of happy about that," Moniak said. "Leading up to the Draft, people didn't buy into what I was as a baseball player, and right now, people aren't fully sold on me, so I'm definitely using that as fuel. I'm excited for this year."